CLEVELAND (AP) — Cavaliers owner Dan Gilbert insists he has moved on from LeBron James. But on to what?

Gilbert has reportedly enlisted a law firm to investigate the circumstances leading to James leaving Cleveland to sign with the Miami Heat this summer.

Yahoo! Sports reported on Wednesday that Gilbert has paid hundreds of thousands of dollars to a Midwestern law firm to investigate suspicions that the Heat broke NBA tampering rules while pursuing James, who left the Cavs after seven seasons to join fellow stars Chris Bosh and Dwyane Wade in Miami.

The timing of the report is interesting since James will return to play in Cleveland for the first time on Thursday night, in what promises to be a hostile Quicken Loans Arena.

On Tuesday, Gilbert, who was highly critical of James following the superstar's televised announcement in July, was asked about his emotions heading into the reunion with the two-time league MVP.

"I'm over it," he said. "I really am. That's the truth. I let it all out in about 24 hours. I just think we have such a great core and a great coaching staff. We have a lot of opportunities with the trade exception and the draft. I feel good about this team."

Team spokesman Tad Carper said Wednesday night the Cavaliers are declining comment on the Yahoo! report, which citing anonymous league sources, says Gilbert plans to present NBA commissioner David Stern with a detailed case with the hopes of launching a tampering investigation.

According to Yahoo's sources, Gilbert will spare no expense to uncover whatever evidence he can to take to the league office and that law firm staff includes several former prosecutors with backgrounds in investigating and constructing cases.

Also, the report states that the firm is probing an alleged meeting between James and Heat president Pat Riley in November 2009 and a meeting between James' inner circle and Wade in Chicago last June.

The report adds another element to James' homecoming, which figures to be an emotional night for the 25-year-old and Cleveland fans.

Gilbert is expected to be in his usual baseline seat next to the Cavaliers bench, where he'll have an up-close view of what promises to be a memorable event.

In the hours after James announced his intentions to leave Cleveland, Gilbert fired off a scathing letter to Cleveland fans in which he lambasted his former star player, calling him "narcisstic" and vowing the Cavaliers would win an NBA title before "the self-declared former King."

Later that night in an interview with The Associated Press, Gilbert accused James of quitting in last season's playoffs.

"He quit," Gilbert said. "Not just in Game 5, but in Games 2, 4 and 6. Watch the tape. The Boston series was unlike anything in the history of sports for a superstar. ... People have covered up for him for way too long."